Blade wheel propeller



July 3, 1956 G. E. FRANZ 2,753,006

BLADE WHEEL PEOPE EER Filed Dec. 24, 1952 INVENT OR Giizil her E Fran;

BLADE WHEEL PROPELLER Gunther E. Franz, Heidenheim (Brenz), Germany, as-

signor to J. M. Voith G. in. b. H., Maschinenfabrik, Heidenheim (Brenz),Germany Application December 24, 1952, Serial No. 327,740

lairns priority, application Germany December 31, 1951 3 Claims. (Cl.170-151) The present invention relates to ship propellers and, moreparticularly, to blade wheel propellers. As is well known, the blades ofblade wheel propellers-cycloidal propellers-are during their rotationabout the propeller axis controlled according to certain laws by a bladedrive mechanism, mostly called kinematics. While in operation, theblades carry out an oscillating movement about their tangentialposition, the amplitude of which may be influenced by the speed lever orspeed stick whereas the phase of said oscillating movement can beinfluenced by the steering wheel.

As blade drive mechanism for high speed cycloidal propellers, thesocalled connecting rod kinematics have proved successful. With thisconstruction, also called sliding link kinematics, the blades arecoupled by means of a blade lever, a connecting rod, and a slide rodwith annular control center which in the zero position of said blades islocated centrally and which is rotatably connected with the propeller inany convenient manner. The said slide rod is guided in a slidemember-cross headwhich is rotatably journalled in the propeller wheel.

In addition to the above, also a number of further kinematics have beensuggested. As far as they have been built, they have at least in partproved successful as to design. However, they could not get adopted bythe ship building industry over the materially simpler connecting rodkinematics. On the other hand, even with the proven connecting rodkinematics, the blade wheel propeller has not been adopted to the extentit would deserve in view of its excellent maneuverability and its simpleoperation. This is due primarily to the fact that is materially higherin price than the screw propeller drive.

in an effort to develop a kinematics as simple and as low in cost aspossible, already two decades ago, the construction of a simplesine-kinematics has been suggested and discussed. Preliminary researchtests, however, have yielded so poor a degree of efliciency ofsine-kinematics that experts in this art have abstained from furthertests and have dismissed the sine-kinematics as completely impractical.Also, in the meantime occasionally advanced suggestions concerning thesine-kinematics have produced no success inasmuch as these suggestionswere expected merely to confirm the results of the above mentionedresearch tests.

More recently it was believed that an explanation of theimpracticability of the sine-kinematics had been found. It had beenfound that with a blade wheel propeller a great angle of attack or bladeangle can be selected without having to fear that a separation of thehow or cavitation will occur. However, it was believed that a sinusoidalblade angle graph in the first range of the front wheel half-ascendingbranch of the sine curve and in, the oppositely located last range ofthe rear wheel hnlfdescending branch of the sine graph-wou1dautomatically cause too fast a rise or drop of the approach flow angleand thus would produce cavitations and losses in efficiency. Thisexplanation further strengthened the ICE heretofore prevailing opinionconcerning the impracticability of the sine-kinematics.

It is, therefore, an object of the present invention to provide a bladewheel cycloidal propeller with sinekinematics which will overcome theabove mentioned drawbacks.

It is another object of this invention so to simplify thesine-kinematics for use in connection with blade wheel cycloidalpropellers that such a construction will not only be able to competewith screw propellers but will have distinct advantages over the latterin connection with certain types of ships or vessels.

These and other objects and advantages of the invention will appear moreclearly from the following specification in connection with theaccompanying drawings in which:

Fig. 1 diagrammatically illustrates a cross section through a propelleraccording to the invention.

Fig. 2 represents a top view of the blade drive linkage.

Fig. 3 is a graph concerning the blade angle in connection with thepropeller according to the present invention.

General arrangement Recent tests have revealed that the heretoforeprevailing opinions concerning the sine-kinematics with blade wheelcycloidal propellers represent an unjustified prejudice, and that withsine-kinematics very favorable results can be obtained provided that theblade wheel driving mechanism yields a sinusoidal blade angle graphwhich for all practical purposes is the same for each and every blade ofthe same blade wheel. The blade angle epsilon plotted over thecircumferential angle phi, should therefore, yield a sine curve, andthis sine curve should for each blade of one and the same blade wheel bepractically the same and equal the sine of the circumferential anglephi. This condition is met by a blade wheel propeller according to theinvention which is characterized in that the inner end of each couplingor connecting rod of one and the same blade wheel ends in an annularmember or portion and that all of said annular members or portions aresuperimposed upon each other and are arranged concentrically with regardto each other and with regard to the lower end portion of the controlmember regardless of the control position of said control member.According to a specific embodiment of the invention the control memberis designed as control stick having a lower ball shaped end. This ballshaped end forms the control center and has pivotally connected theretothe inner ends of all coupling rods which in their turn are connected tothe blade levers. The arrangement is such that the respectivelongitudinal axis of each of said connecting rod means intersects theaxis of said control means in all positions of said control meanswhereby substan-.

tially the same sinusoidal blade angle curve is obtained for each ofsaid blades.

Structural arrangement Referring now to the drawings in detail and Fig.1 thereof in particular, the arrangement shown therein comprises ahollow shaft 1 through the intervention of which the wheel 2 of thepropeller is rotated. The wheel 2 is in a manner known per se carried bya part 3 which extends into the hollow shaft 1 and pertains to astationary casing (not shown in the drawing). The blade 4', 4 and 4 arerotatably journalled in the wheel 2. Respectively slipped over the bladepivots 5, 5, 5 are blade levers 6, 6, 6" having pivotally connectedthereto at 100, 100" coupling or connecting rods 7, 7a and 7brespectively. The inner end of each of said coupling rods 7, 7a, 7b endsin an annular portion 7', 7a, and 7b,

respectively. Said annular portions are arranged concen-. trically withregard to each other and concentrically ex" tend around the ball box 9at the lower ball-shaped end 10'1'1 of the 'cont'rofsticklfl "will beelearrrsn the drawings, the coupling rods 7, 7a, 7b are arranged at derent le lsl sete ab v a o her- T e ner end 75"'orthsintrmeainecou lingsemis d' (1 g bushin qt a height which equals'the dis an between tie uper surface of annular portion '7' and the bottom Q 111 .113; portion'lb.It will also be noted from the"drawing'that the annular portion 7aincludes, an annular section '7. separating the annular portions 7.-'and 'Z'bj. fforn" "Chothe'r'." Furthermorefthe annular portions of? thecoupling rods areslidably mounted'between the, upper an I1, of the wheel2 and an intermediate wan 12. For, purposes" or simplification or thedrawing, Fig 1 shows the two "blades 4" and 471 f Fig. 2 as if theywereszcatedint e amepl eho'wsf'thetwo blades with their control system nfor, speed ahead'the traveling direction inap' anigindica'tea bihe'arrow 13; AS will be" seen rom Fig, 2,, also when the center of ball10;: by actuatioii or stick 10 has been moved in o an eccentric positionwith regard to the fort the circle on which the tilting. axes b and 41"are located, the center of 11 ltlfand the center of the annular portions7,

7a" and '7b"still remain located on one and the same line.

This may also be expressed in a different way namely e ard es of e contol pos tion of h control sti k rash-en eri g 7",7a arid Vb" pass throughthe same lih'e whichfin Fig, 2 is represented as an intersecting pointor the projection of the axes 7 7a" and 7b".

3 'shov' vs th'e blade angle epsilon plotted over the H ferential anglephi and also shows the sine graph obtained thereby. This sine graph isthe same for'each andall'o'f theblad es 4 4," and4'.

Tests carried outwith a propeller having a sine kinemataccording to thepresent invention have proved that suchia propeller is particularlyadvantageous when used as a 'p 'opeller with a medium or high loadingfactor, in other as propeller for slowly. travelling, relatively heavyrich as tug boats, floating cranes, or the like. 'purp'oses,"the bladewheel. pt peller'according e sent invention may be further simplified byreg uci g the numberjof blades as far as possible so that the, I a i bpdPlYT iP h e Wid bl de It h been found that small number of blades isparticu l ly 'a drnissible for slowly running propellers whereas,

Ablfadewheel propeller according to thepre ent invention is therefio'refundamentally simpler than any. other known" desi'gnsf'The blade driverod system for each ic m t ling rod which, is centrally pivotallyconnected,- toa eope'rable by the, control stick 10, The. blade '6 andthe; coupling rods, 7, 7a and 7b, with, the exception of their innerannular portions" may respec: tively all be of the same design.Furthermore, a carrier device for the control center for a synchronousor isochronous, carryingalong of the, control center by means of th ewheelbodyis' superfluous according to the pre se nt.

invention, The, factor thatonlythrceblades are required for a reliableoperation ofv the propeller, materially contributes toa: simplificationand-a reduction in. costof the It, is, ofjcourse, understood, thatthepresent invention. r ng, means, imi d e, r c larn ruc ion.

s in addition to the blade lever onl'y one controlfpivot which may in amanner known shown in the drawings but also comprises any modificatrans"wnaiameseo'pssr the appended claims.

What I claim is:

1. In a blade wheel ship propeller arrangement having a rotatable wheelwith a plurality of blades respectively provided with shafts operable tooscillate said blades about the respective axes of said shafts, thecombination of: a plurality or blade lever means respectively connec edt said shafts pluralit of nect n o means. having their, outer efudsrespectively. pivotally connected to said blade lever means, the'inner.ends of said connecting rod means being formed with annular portionsarranged concentrically with regard to each other and superimposed uponeach omen, and c n rol me ns 011- centrically surrounded by said annularportions and operable selectively to'shift the said annular portionsfrom a position concentric to said rotatable wheel into a plurality ofpositions eccentric thereto and vice versa, the respective longitudinalaxisof each. of said, connecting rod means intersecting the axis of saidcontrol means in all positions ot's'aid control means wherebysubstantially the same sinusoidal blade angle'curve is obtained for eachof said bladesj In a blade, wheel ship propeller arrangement whichincludes a rotatable; wheel 'with oppositely located spaced central wallsections extending substantially perpendicular to the axis of rotationof said wheel, and, in which said rotatable wheel carries a plurality ofblades respectively provided with shafts operable, to oscillate saidblades about the respective axes of said shafts, the combination of: aplurality of. blade lever means respectively connected to said shafts,a; plurality of connecting rod means having their. outer endsvrespectively pivotally connected to said blade. lever. means, the innerends of said connecting' rod means being. formed with. annular fiatportions concentrically arranged with regard to. each other andsuperimposed upon, each other, said annular portions being journalledbetween. said; oppositely located spaced central wall sections of saidwheel so as to allow oscillation 'of said annular portionsrela tive. toeach. other, ball bo'imeans mounted within said. annular'fportions, andcontrol stick' means including a. ball-shaped portion jourhalled, insaid ball box means and operable selectively to shift said annular.portions from a position concentric to said rotatableiwheel into aplurality of positions efccehtrici'the reto andvic'e versa, therespective longitudinal arises eacho' fl said connecting rod meansintersecting the. axis of said control. rneansfin, all positions of saidcontrol. means whereby, substantially the same sinusoidal blade anglecurve is obtained for each of said blades.

3. In a bladewheel ship propeller. arrangement having a rotatable wheelwithan uneven number of blades respectivelyprovided with shafts operableto oscillate said bladesabout therespective axes of said shafts, thecombination of: a plurality of blade lever means correspondingjn number.to that'of said'blades andrespectively connected; to said; shafts, aplurality ofconnecting rod means, corresponding in number to that ofsaid blades and having, theirouten ends respectively pivotally connectedtosaidblade levermeans, theinnerfendsof'said connectingrodmeansflbeingiformed with annular portions concentrically arranged withregard to each other and superimposedupon each, other, said. annularportions being supportedbysaid. wheel and being oscillatable relativetheretoand relative to eachiotherfthat, annular portion whichhasthensamernumber oft-annular. portions arranged above and, belowthereof; having integral therewith a sleeve, concentrically locatedwithin said. other annular portions, and control, means concentricallysurrounded bysaidannular.portions and operable selectively to shift.

all -ofsaid annular portions asaunit frornaposition concentric to said.rotatablewheel intoa plurality of positions eccentric thereto and: vice.versa, the respective longitudinal-,axisof each. ofrsaidrconnectinglrodimeans intersectng,thea iis ofssfldacontrol:rneans. in.all-.positions.oflsaid 5 control means whereby substantially the same sinusoidal2,250,772 blade angle curve is obtained for each of said blades.2,580,428

References Cited in the file of this patent UNITED STATES PATENTS 52,037,069 Ehrhart Apr. 14, 1936 1313:7117

6 Mueller et a1 July 29, 1941 Heuver Jan. 1, 1952 FOREIGN PATENTSGermany June 15, 1951 Germany Nov. 29, 1951 France Aug. 4, 1952

